Discussion—Müller-Lyer Illusion THIS IS ONLY A 300 TO 500 WORD DISCUSSION -

Assignment 1: Discussion—Müller-Lyer Illusion Whenever you think about illusions, names of magicians such as Harry Houdini and David Copperfield probably come to mind. However, in the visual system, illusions are often evidence of how the perceptual system “changes” what was actually detected by the sensory system. Experience teaches us to expect certain perceptual relationships among stimuli. Illusions often take advantage of these expectations. Access the CogLab demonstration “Müller-Lyer” and follow the instructions to complete the demonstration. Based on the demonstration, respond to the following: ****Describe how difficult this task was in your opinion. How accurate do you think you were in this task? Looking at your individual data, explain whether your results support the feelings you had about your performance. Describe what your data would look like if you suppose that the wings of the comparison line were drawn inward instead of outward in the demonstration. Describe an everyday situation that could partly explain the Müller-Lyer illusion. Write your initial response in 300–500 words. Apply APA standards to citation of sources.. BELOW IS THE SPECIFICS OF THE COG LAB: Muller-Lyer Illusion What methods did we employ in this experiment? On each trial, two vertical lines were shown. One line had the outward-drawn wings to make the Muller-Lyer stimulus and was always the same size. The other (comparison) line had no wings and its length varied from trial to trial. Your task was to choose which vertical line was longer on a given trial. The independent variable in this experiment was the length of the comparison line. The dependent variable was the proportion of trials in which you reported that the Muller-Lyer line was longer than the comparison line. What do we predict participants will do? Why? The graph plots the proportion of trials in which the comparison line was reported as longer than the Muller-Lyer line. The Muller-Lyer line was always 100 pixels long. The x-axis gives the pixel length of the comparison line. The Muller-Lyer illusion is that the line with wings appears to be longer than a line without wings. Typical data shows that proportions are close to zero on the left and increase toward one on the far right. If there was no illusion, the line would be at approximately 0.5 for a comparison line with a length of 100 pixels. Evidence of the illusory effect would be when the 0.5 proportion is for a pixel length greater than 100 pixels. How robust is this effect? Are there limits to this effect? The Muller-Lyer illusion is one of the most studied illusions in cognitive psychology. It has been replicated thousands of times. The strength of the illusion can be varied by changing the properties of the line, the wings, and the context in which the stimuli are placed. Data summary for experiment Muller-Lyer Illusion. If you click on the 'Data plot' tab, you will see a graph of the results shown below. The graph plots the proportion of trials you chose the vertical line without wings as bigger than the line with wings. The line with wings was always 100 pixels long. The x-axis gives the pixel length of the line without wings. The Muller-Lyer illusion is that the line with wings appears to be longer than a line without wings. Typical data shows that proportions are close to zero on the left and increase toward one on the far right. If there was no illusion, the line would be at approximately 0.5 for a line without wings length of 100 pixels. Evidence of the illusory effect would be when the 0.5 proportion is for a pixel length greater than 100 pixels. Data summary Size of line without wings (pixels) Proportion of line w/o wings bigger 85.0 0.0 88.0 0.0 91.0 0.0 94.0 0.0 97.0 0.0 100.0 0.0 103.0 0.0 106.0 0.0 109.0 0.1 112.0 0.3 115.0 0.4 118.0 0.3 121.0 0.5 124.0 0.6 127.0 0.8 Trial-by-trial data The Muller-Lyer (with wings) line has a size of 100 pixels. The second column gives the length of the comparison (without wings) line. The choice is which vertical line was reported as bigger. Trial Size of line without wings (pixels) Choice 1 130.0 With wings 2 100.0 With wings 3 97.0 With wings 4 100.0 With wings 5 109.0 With wings 6 94.0 With wings 7 130.0 Without wings 8 106.0 With wings 9 118.0 With wings 10 103.0 With wings 11 112.0 Without wings 12 94.0 With wings 13 115.0 With wings 14 121.0 With wings 15 118.0 Without wings 16 88.0 With wings 17 100.0 With wings 18 121.0 Without wings 19 97.0 With wings 20 124.0 Without wings 21 127.0 Without wings 22 97.0 With wings 23 91.0 With wings 24 109.0 With wings 25 112.0 With wings 26 106.0 With wings 27 106.0 With wings 28 112.0 With wings 29 121.0 With wings 30 109.0 With wings 31 127.0 Without wings 32 115.0 With wings 33 91.0 With wings 34 124.0 Without wings 35 94.0 With wings 36 127.0 Without wings 37 115.0 Without wings 38 121.0 With wings 39 103.0 With wings 40 115.0 With wings 41 88.0 With wings 42 103.0 With wings 43 97.0 With wings 44 91.0 With wings 45 100.0 With wings 46 100.0 With wings 47 118.0 Without wings 48 115.0 With wings 49 118.0 With wings 50 124.0 Without wings 51 103.0 With wings 52 106.0 With wings 53 121.0 Without wings 54 100.0 With wings 55 88.0 With wings 56 127.0 Without wings 57 112.0 With wings 58 112.0 With wings 59 97.0 With wings 60 109.0 With wings 61 115.0 With wings 62 100.0 With wings 63 130.0 With wings 64 97.0 With wings 65 97.0 With wings 66 94.0 With wings 67 115.0 Without wings 68 109.0 With wings 69 103.0 With wings 70 127.0 With wings 71 97.0 With wings 72 88.0 With wings 73 121.0 With wings 74 94.0 With wings 75 112.0 With wings 76 100.0 With wings 77 118.0 With wings 78 88.0 With wings 79 112.0 With wings 80 115.0 Without wings 81 112.0 Without wings 82 106.0 With wings 83 130.0 Without wings 84 127.0 With wings 85 130.0 Without wings 86 103.0 With wings 87 88.0 With wings 88 127.0 Without wings 89 127.0 Without wings 90 121.0 Without wings 91 97.0 With wings 92 106.0 With wings 93 121.0 With wings 94 91.0 With wings 95 124.0 Without wings 96 130.0 Without wings 97 103.0 With wings 98 100.0 With wings 99 118.0 With wings 100 130.0 Without wings 101 112.0 With wings 102 124.0 Without wings 103 94.0 With wings 104 94.0 With wings 105 91.0 With wings 106 106.0 With wings 107 88.0 With wings 108 106.0 With wings 109 106.0 With wings 110 124.0 Without wings 111 109.0 Without wings 112 109.0 With wings 113 124.0 With wings 114 124.0 With wings 115 118.0 With wings 116 91.0 With wings 117 88.0 With wings 118 94.0 With wings 119 88.0 With wings 120 91.0 With wings 121 103.0 With wings 122 124.0 With wings 123 118.0 With wings 124 91.0 With wings 125 118.0 Without wings 126 115.0 With wings 127 109.0 With wings 128 94.0 With wings 129 118.0 With wings 130 106.0 With wings 131 109.0 With wings 132 115.0 Without wings 133 112.0 Without wings 134 91.0 With wings 135 121.0 Without wings 136 100.0 With wings 137 130.0 Without wings 138 97.0 With wings 139 121.0 Without wings 140 130.0 With wings 141 103.0 With wings 142 127.0 Without wings 143 130.0 With wings 144 124.0 With wings 145 88.0 With wings 146 109.0 With wings 147 103.0 With wings 148 127.0 Without wings 149 91.0 With wings